Compared head-on, the F-117A and the F-22 don’t look very similar. But turn one picture upside down and the relationship is suddenly very clear.

Lockheed’s original Advanced Tactical Fighter design was very closely based on the F-117—or, to be more exact, what a second-generation F-117 might have been, with curved wing and tail surfaces, rounded edges, and new, lighter radar-absorbing materials. In turn, Lockheed’s F-35 Lightning II, intended to be the linchpin of both U.S. and allied fighter forces for much of this century, is clearly a cousin of the F-22. These designs reflect a philosophy that remains unique to the Air Force: that a fighter should be designed primarily around stealth.

The U.S. Navy and European air forces have elected to build fighters (the Boeing Super Hornet, the Dassault Rafale, and the Eurofighter Typhoon) that use stealth technology to render hostile radars less effective, but are basically conventional, with weapon carriages and electronic jamming systems located outside the aircraft.

Dassault describes the Rafale fighter as not stealthy (“furtif”) but discreet (“discret”), using a combination of stealth and low flying to avoid detection. Not surprisingly, Eurofighter and Dassault people claim that their aircraft are quite as capable as the F-35. They may not be as stealthy but they carry more weapons for attack and defense, and if you need the ultimate in stealth for certain targets, both fighters will carry missiles that can reach targets before the airplanes are in range of defenses.

But the biggest influence the F-117 exerted on the F-35 is doctrinal. The way that the new jet uses stealth is rooted in the F-117A’s experience in the first Gulf War, which the planners had in mind when drawing up the specifications for the Joint Strike Fighter program (which developed the F-35) back in 1995.

In that conflict, the F-117As had played the leading role in lobotomizing the Soviet-supplied Iraqi air defense system, allowing F-16s and F-15s to operate with relative impunity for the rest of the campaign.

Faced with the task of building a tactical stealth attack aircraft that would cost less than the big, canceled A-12 Avenger II, Pentagon planners came up with a concept called “day one stealth”: For the first missions of the war, the JSF would be a stealthy airplane with a limited bomb load, like the F-117, but once the enemy’s defenses had been destroyed, it could be loaded with external weapons like the older fighters.

It’s a great idea if it works—but the lesson from Serbia was that it did not, for two reasons. The air defenses did not want to get killed on the first night, so they sacrificed lethality for mobility, minimized the use of radar, and survived to harry the attackers throughout the campaign. They also abandoned the centralized Russian control model and improvised communications, using telephones.

Last May, a Russian television documentary partly lifted the veil on that country’s stealth and counter-stealth research, showing that engineers there had reproduced and studied the signatures of U.S. stealth aircraft and exploited their vulnerability to long-wave radars since the 1980s.